/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <locale.h>
#include <cryptoutil.h>

/*
 * Read file into buffer.  Used to read raw key data or initialization
 * vector data.  Buffer must be freed by caller using free().
 *
 * If file is a regular file, entire file is read and dlen is set
 * to the number of bytes read.  Otherwise, dlen should first be set
 * to the number of bytes requested and will be reset to actual number
 * of bytes returned.
 *
 * Return 0 on success and errno on error.
 */
int
pkcs11_read_data(char *filename, void **dbuf, size_t *dlen)
{
        int     fd = -1;
        struct stat statbuf;
        boolean_t plain_file;
        void    *filebuf = NULL;
        size_t  filesize = 0;
        int ret = 0;

        if (filename == NULL || dbuf == NULL || dlen == NULL)
                return (-1);

        if ((fd = open(filename, O_RDONLY | O_NONBLOCK)) == -1) {
                ret = errno;
                cryptoerror(LOG_STDERR, gettext("cannot open %s"), filename);
                goto error;
        }

        if (fstat(fd, &statbuf) == -1) {
                ret = errno;
                cryptoerror(LOG_STDERR, gettext("cannot stat %s"), filename);
                goto error;
        }

        if (S_ISREG(statbuf.st_mode)) {
                /* read the entire regular file */
                filesize = statbuf.st_size;
                plain_file = B_TRUE;
        } else {
                /* read requested bytes from special file */
                filesize = *dlen;
                plain_file = B_FALSE;
        }

        if (filesize == 0) {
                /*
                 * for decrypt this is an error; for digest this is ok;
                 * make it ok here but also set dbuf = NULL and dlen = 0
                 * to indicate there was no data to read and caller can
                 * retranslate that to an error if it wishes.
                 */
                (void) close(fd);
                *dbuf = NULL;
                *dlen = 0;
                return (0);
        }

        if ((filebuf = malloc(filesize)) == NULL) {
                ret = errno;
                cryptoerror(LOG_STDERR, gettext("malloc: %s"), strerror(ret));
                goto error;
        }

        if (plain_file) {
                /* either it got read or it didn't */
                if (read(fd, filebuf, filesize) != filesize) {
                        ret = errno;
                        cryptoerror(LOG_STDERR,
                            gettext("error reading file %s: %s"), filename,
                            strerror(ret));
                        goto error;
                }
        } else {
                /* reading from special file may need some coaxing */
                char    *marker = (char *)filebuf;
                size_t  left = filesize;
                ssize_t nread;

                for (/* */; left > 0; marker += nread, left -= nread) {
                        /* keep reading it's going well */
                        nread = read(fd, marker, left);
                        if (nread > 0 || (nread == 0 && errno == EINTR)) {
                                errno = 0;
                                continue;
                        }

                        /* might have to be good enough for caller */
                        if (nread == 0 && errno == EAGAIN)
                                break;

                        /* anything else is an error */
                        if (errno) {
                                ret = errno;
                                cryptoerror(LOG_STDERR,
                                    gettext("error reading file %s: %s"),
                                    filename, strerror(ret));
                                goto error;
                        }
                }
                /* reset to actual number of bytes read */
                filesize -= left;
        }

        (void) close(fd);
        *dbuf = filebuf;
        *dlen = filesize;
        return (0);

error:
        if (fd != -1)
                (void) close(fd);

        return (ret);
}